Production of oil seed protein isolate

ABSTRACT

Oil seed protein isolates, particularly canola protein isolate, are produced at a high purity level of at least about 100 wt % (Nx 6.25) by a process wherein oil seed protein is extracted from oil seed meal, the resulting aqueous protein solution is concentrated to a protein content of at least about 200 g/L, and the concentrated protein solution is added to chilled water having a temperature below about 15° C. to form protein micelles, which are settled to provide a protein micellar mass (PMM). The protein micellar mass is separated from supernatant and may be dried. The supernatant may be processed to recover additional oil seed protein isolate by concentrating the supernatant and then drying the concentrated supernatant, to produce a protein isolate having a protein content of at least about 90 wt %. The concentrated supernatant may be mixed in varying proportions with at least part of the PMM and the mixture dried to produce a protein isolate having a protein content of at least about 90 wt %.

REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC 119(e) from copending U.S.Patent application No. 60/288,415 filed May 4, 2001, No. 60/326,987filed Oct. 5, 2001, No. 60/331,066 filed Nov. 7, 2001, No. 60/333,494filed Nov. 26, 2001 and ______ filed ______.

FIELD OF THE INVENTION

The present invention relates to improved methods for manufacturing oilseed protein isolate, particularly a canola protein isolate.

BACKGROUND TO THE INVENTION

In U.S. Pat. Nos. 5,844,086 and 6,005,076 (“Murray II”), assigned to theassignee hereof and the disclosures of which are incorporated herein byreference, there is described a process for the isolation of proteinisolates from oil seed meal having a significant fat content, includingcanola oil seed meal having such content. The steps involved in thisprocess include solubilizing proteinaceous material from oil seed meal,which also solubilizes fat in the meal, and removing fat from theresulting aqueous protein solution. The aqueous protein solution may beseparated from the residual oil seed meal before or after the fatremoval step. The defatted protein solution then is concentrated toincrease the protein concentration while maintaining the ionic strengthsubstantially constant, after which the concentrated protein solutionmay be subjected to a further fat removal step. The concentrated proteinsolution then is diluted to cause the formation of a cloud-like mass ofhighly associated protein molecules as discrete protein droplets inmicellar form. The protein micelles are allowed to settle to form anaggregated, coalesced, dense, amorphous, sticky, gluten-like proteinisolate mass, termed “protein micellar mass” or PMM, which is separatedfrom the residual aqueous phase and dried.

The protein isolate has a protein content (as determined by KjeldahlNx6.25) of at least about 90 wt %, is substantially undenatured (asdetermined by differential scanning calorimetry) and has a low residualfat content. The term “protein content” as used herein refers to thequantity of protein in the protein isolate expressed on a dry weightbasis. The yield of protein isolate obtained using this procedure, interms of the proportion of protein extracted from the oil seed mealwhich is recovered as dried protein isolate was generally less than 40wt %, typically around 20 wt %.

The procedure described in the aforementioned Murray II patent wasdeveloped as a modification to and improvement on the procedure forforming a protein isolate from a variety of protein source materials,including oil seeds, as described in U.S. Pat. No. 4,208,323 (MurrayIB). The oil seed meals available in 1980, when U.S. Pat. No. 4,208,323issued, did not have the fat contamination levels of the canola oil seedmeals available at the time of the Murray II patents, and, as aconsequence, the procedure of U.S. Pat. No. 4,208,323 cannot producefrom such oil seed meals processed according to the Murray II process,proteinaceous materials which have more than 90 wt % protein content.There is no description of any specific experiments in U.S. Pat. No.4,208,303 carried out using rapeseed (canola) meal as the startingmaterial.

U.S. Pat. No. 4,208,323 itself was designed to be an improvement on theprocess described in U.S. Pat. Nos. 4,169,090 and 4,285,862 (Murray IA)by the introduction of a concentration step prior to dilution to formthe PMM. The Murray IA patents describe one experiment involvingrapeseed but provides no indication of the purity of the product. Theconcentration step described in the Murray IB patent served to improvethe yield of protein isolate from around 20% for the Murray IA process.

SUMMARY OF INVENTION

It has now been found that it is possible to improve these prior artprotein isolate processes as they apply to oil seeds, particularlycanola, to obtain improved yields of dried protein isolate, in terms ofthe proportion of protein extracted from the oil seeds, of at leastabout 40 wt % and often much higher, at least about 80 wt %, and proteinisolates of higher purity, at least about 100 wt % at a Kjeldahlnitrogen conversion rate of Nx6.25.

It has further been found that a significant proportion of the canolaprotein extracted from the meal in the process of Murray IA and IB andMurray II, as applied to canola meal, is lost as a result of discardingthe supernatant from the PMM-formation step. A further improvement onthe prior procedure is provided herein, which improves the overall yieldof protein, wherein protein present in the supernatant is recoveredgenerally by a process of concentration to remove impurities and dryingthe concentrate. The product obtained from the supernatant generally hasa protein content (Nx6.25) of greater than 100% and is a novel canolaprotein isolate product. Such novel product provides a further aspect ofthe invention.

As a further improvement on the prior procedure, the concentratedsupernatant may be mixed with the PMM and the mixture dried.Alternatively, a portion of the concentrated supernatant may be mixedwith at least a portion of the PMM and the resulting mixture dried. Thelatter products are novel canola protein isolate products and constitutea further aspect of the invention.

In accordance with one aspect of the present invention, there isprovided a process of preparing a protein isolate, which comprises (a)extracting an oil seed meal at a temperature of at least about 5° andpreferably up to about 35° C. to cause solubilization of protein in saidoil seed meal and to form an aqueous protein solution having a proteincontent of about 5 to about 25 g/L and a pH of about 5 to about 6.8, (b)separating the aqueous protein solution from residual oil seed meal, (c)increasing the protein concentration of said aqueous protein solution toat least about 200 g/L while maintaining the ionic strengthsubstantially constant by using a selective membrane technique toprovide a concentrated protein solution, (d) diluting said concentratedprotein solution into chilled water having a temperature of below about15° C. to cause the formation of protein micelles; (e) settling theprotein micelles to form an amorphous, sticky, gelatinous gluten-likeprotein micellar mass, and (f) recovering the protein micellar mass fromsupernatant having a protein content of at least about 100 wt % asdetermined by Kjeldahl nitrogen x6.25 on a dry weight basis. Therecovered protein micellar mass may be dried. The protein isolate issubstantially undenatured (as determined by differential scanningcalorimetry).

The protein isolate product in the form of protein micellar mass isdescribed herein as “gluten-like”. This description is intended toindicate the appearance and feel of the isolate are similar to those ofvital wheat gluten and is not intended to indicate chemical identity togluten.

In one embodiment of this process, supernatant from the settling step isconcentrated and the resulting concentrated supematant is dried toprovide a protein isolate having a protein content of at least about 90wt % (Nx 6.25) on a dry weight basis. Such protein isolate is a novelproduct and is provided in accordance with further aspect of theinvention.

In another embodiment of this process, supernatant from the settlingstep is concentrated, the resulting concentrated supernatant is mixedwith the protein micellar mass prior to drying the same, and theresulting mixture is dried to provide a protein isolate having a proteincontent of at least about 90 wt % (Nx 6.25) on a dry weight basis. Suchprotein isolate is a novel product and is provided in accordance withanother aspect of the invention.

In a further embodiment of the invention, supernatant from the resultingstep is concentrated and a portion only of the resulting concentratedsupernatant is mixed with at least a portion of the protein micellarmass prior to drying the same to provide other novel protein isolatesaccording to the invention having a protein content of at least about 90wt % (Nx 6.25) on a dry weight basis.

A key step in the process of the present invention and the ability toobtain higher yields of protein isolate at purities of at least 100 wt %than previously attained is concentration of the protein solution to aprotein content of at least about 200 g/L, a much higher value than inthe prior procedures described above. Another key step is the step ofwarming the concentrated protein solution, as necessary, prior todilution into chilled water at a dilution rate of less than 1:15, whenprotein micellar mass only is recovered. This specific combination ofparameters is not described in the prior art nor are the beneficialresults of high protein yield and high purity protein isolate describedtherein. An additional step in improving protein yield, particularly inthe case of canola meal, is the recovery of additional quantities ofprotein from the supernatant from the PMM formation and settling step.

In accordance with another aspect of the invention, there is provided aprocess for preparing a canola protein isolate of reduced pigmentation,which comprises (a) extracting canola oil seed meal at a temperature ofat least 5° C. to cause solubilization of protein in said canola oilseed meal and to form an aqueous protein solution having a proteincontent of about 5 to about 25 g/L and a pH of about 5 to about 6.8; (b)separating the aqueous protein solution from residual canola oil seedmeal; (c) subjecting the aqueous protein solution to a pigment removalstep; (d) increasing the protein concentration of said aqueous proteinsolution to at least about 200 g/L while maintaining the ionic strengthsubstantially constant by using a selective membrane technique toprovide a concentrated protein solution; (e) diluting said concentratedprotein solution into chilled water having a temperature below about 15°C. to cause the formation of protein micelles; (f) settling the proteinmicelles to form an amorphous, sticky, gelatinous, gluten-like micellarmass; and (g) recovering the protein micellar mass from supernatanthaving a protein content of at least about 90 wt % as determined byKjeldahl nitrogen x6.25 on a dry weight basis.

The protein isolate produced according to the process herein may be usedin conventional applications of protein isolates, such as, proteinfortification of processed foods, emulsification of oils, body formersin baked goods and foaming agents in products which entrap gases. Inaddition, the protein isolate may be formed into protein fibers, usefulin meat analogs, may be used as an egg white substitute or extender infood products where egg white is used as a binder. The canola proteinisolate may be used as nutritional supplements. Other uses of the canolaprotein isolate are in pets foods, animal feed and in industrial andcosmetic applications and in personal care products.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic flow sheet of a procedure for producing an oilseed protein isolate as well as other products in accordance with oneembodiment of the invention.

GENERAL DESCRIPTION OF INVENTION

The initial step of the process of this invention involves solubilizingproteinaceous material from oil seed meal, particularly canola meal,although the process may be applied to other oil seed meals, such assoybean, traditional rapeseed, traditional flax, linola, sunflower andmustard oil seed meals. The invention is more particularly describedherein with respect to canola seed meal.

The proteinaceous material recovered from canola seed meal may be theprotein naturally occurring in canola seed or other oil seed or theproteinaceous material may be a protein modified by genetic manipulationbut possessing characteristic hydrophobic and polar properties of thenatural protein. The canola meal may be any canola meal resulting fromthe removal of canola oil from canola oil seed with varying levels ofnon-denatured protein, resulting, for example, from hot hexaneextraction or cold oil extrusion methods. The removal of canola oil fromcanola oil seed usually is effected as a separate operation from theprotein isolate recovery procedure of the present invention.

Protein solubilization is effected most efficiently by using a foodgrade salt solution since the presence of the salt enhances the removalof soluble protein from the oil seed meal. The food grade salt usuallyis sodium chloride, although other salts, such as, potassium chloride,may be used. The food grade salt solution has an ionic strength of atleast about 0.10, preferably at least about 0.15, to enablesolubilization of significant quantities of protein to be effected. Asthe ionic strength of the salt solution increases, the degree ofsolubilization of protein in the oil seed meal initially increases untila maximum value is achieved. Any subsequent increase in ionic strengthdoes not increase the total protein solubilized. The ionic strength ofthe food grade salt solution which causes maximum protein solubilizationvaries depending on the salt concerned and the oil seed meal chosen.

In view of the greater degree of dilution required for proteinprecipitation with increasing ionic strengths, it is usually preferredto utilize an ionic strength value less than about 0.8, and morepreferably a value of about 0.15 to about 0.6.

The salt solubilization of the protein is effected at a temperature ofat least about 5° C., preferably up to about 35° C., preferablyaccompanied by agitation to decrease the solubilization time, which isusually about 10 to about 60 minutes. It is preferred to effect thesolubilization to extract substantially the maximum amount of proteinfrom the oil seed meal, so as to provide an overall high product yield.

The lower temperature limit of about 5° C. is chosen sincesolubilization is impractically slow below this temperature while thepreferred upper temperature limit of about 35° C. is chosen since theprocess becomes uneconomic at higher temperature levels in a batch mode.

The aqueous food grade salt solution and the oil seed meal have anatural pH of about 5 to about 6.8 to enable the protein isolate to beformed by the micellar route, as described in more detail below. Theoptimum pH value for maximum yield of protein isolate varies dependingon the oil seed meal chosen.

At and close to the limits of the pH range, protein isolate formationoccurs only partly through the micelle route and in lower yields thanattainable elsewhere in the pH range. For these reasons, pH values ofabout 5.3 to about 6.2 are preferred.

The pH of the food grade salt solution may be adjusted to any desiredvalue within the range of about 5 to about 6.8 for use in the extractionstep by the use of any convenient food grade acid, usually hydrochloricacid, or food grade alkali, usually sodium hydroxide, as required.

The concentration of oil seed meal in the food grade salt solutionduring the solubilization step may vary widely. Typical concentrationvalues are about 5 to about 15% w/v.

The protein extraction step with the aqueous salt solution has theadditional effect of solubilizing fats which may be present in thecanola meal, which then results in the fats being present in the aqueousphase.

The protein solution resulting from the extraction step generally has aprotein concentration of about 5 to about 30 g/L, preferably about 10 toabout 25 g/L.

The aqueous phase resulting from the extraction step then may beseparated from the residual canola meal, in any convenient manner, suchas by employing vacuum filtration, followed by centrifugation and/orfiltration to remove residual meal. The separated residual meal may bedried for disposal.

The colour of the final canola protein isolate can be improved in termsof light colour and less intense yellow by the mixing of powderedactivated carbon or other pigment adsorbing agent with the separatedaqueous protein solution and subsequently removing the adsorbent,conveniently by filtration, to provide a protein solution. Diafiltrationof the separated aqueous protein solution also may be used for pigmentremoval.

Such pigment removal step may be carried out under any convenientconditions, generally at the ambient temperature of the separatedaqueous protein solution, employing any suitable pigment adsorbingagent. For powdered activated carbon, an amount of about 0.025% to about5% w/v, preferably about 0.05% to about 2% w/v, is employed.

Where the canola seed meal contains significant quantities of fat, asdescribed in the Murray II patents, then the defatting steps describedtherein may be effected on the separated aqueous protein solution and onthe concentrated aqueous protein solution. When the colour improvementstep is carried out, such step may be effected after the first defattingstep.

As an alternative to extracting the oil seed meal with an aqueous foodgrade salt solution, such extraction may be made using water alone,although the utilization of water alone tends to extract less proteinfrom the oil seed meal than the aqueous food grade salt solution. Wheresuch alternative is employed, then the food grade salt, in theconcentrations discussed above, may be added to the protein solutionafter separation from the residual oil seed meal in order to maintainthe protein in solution during the concentration step described below.When a colour removal step and/or a first fat removal step is carriedout, the food grade salt generally is added after completion of suchoperations.

Another alternative procedure is to extract the oil seed meal with thefood grade salt solution at a relatively high pH value about 6.8,generally up to about 9.8. The pH of the food grade salt solution, maybe adjusted in pH to the alkaline value by the use of any convenientfood-grade alkali, such as aqueous sodium hydroxide solution. Where suchalternative is employed, the aqueous phase resulting from the oil seedmeal extraction step then is separated from the residual canola meal, inany convenient manner, such as by employing vacuum filtration, followedby centrifugation and/or filtration to remove residual meal. Theseparated residual meal may be dried for disposal.

The aqueous protein solution resulting from the high pH extraction stepthen is pH adjusted to the range of about 5 to about 6.8, preferablyabout 5.3 to about 6.2, as discussed above, prior to further processingas discussed below. Such pH adjustment may be effected using anyconvenient food grade acid, such as hydrochloric acid.

The aqueous protein solution then is concentrated to increase theprotein concentration thereof while maintaining the ionic strengththereof substantially constant. Such concentration is effected toprovide a concentrated protein solution having a protein concentrationof at least about 200 g/L, preferably at least about 250 g/L.

The concentration step may be effected by any convenient selectivemembrane technique, such as ultrafiltration or diafiltration, usingmembranes, such as hollow-fibre membranes or spiral-wound membranes,with a suitable molecular weight cut-off, such as about 3000 to about50,000 daltons, having regard to differing membrane materials andconfigurations.

The concentration step may be effected at any convenient temperature,generally about 20° C. to about 60° C., and for the period of time toeffect the desired degree of concentration. The temperature and otherconditions used to some degree depend upon the membrane equipment usedto effect the concentration and the desired protein concentration of thesolution.

The concentrating of the protein solution to a concentration above about200 g/L in this step, significantly beyond levels previouslycontemplated and attained when employing the Murray I and Murray IIprocesses, not only increases the process yield to levels above about 40wt % in terms of the proportion of extracted protein which is recoveredas dried protein isolate, preferably above about 80 wt %, but alsodecreases the salt concentration of the final protein isolate afterdrying. The ability to control the salt concentration of the isolate isimportant in applications of the isolate where variations in saltconcentrations affect the functional and sensory properties in aspecific food application.

As is well known, ultrafiltration and similar selective membranetechniques permit low molecular weight species to pass therethroughwhile preventing higher molecular weight species from so doing. The lowmolecular weight species include not only the ionic species of the foodgrade salt but also low molecular weight materials extracted from thesource material, such as, carbohydrates, peptides, pigments andanti-nutritional factors, as well as any low molecular weight forms ofthe protein. The molecular weight cut-off of the membrane is usuallychosen to ensure retention of a significant proportion of the protein inthe solution, while permitting contaminants to pass through havingregard to the different membrane materials and configurations.

Depending on the temperature employed in the concentration step, theconcentrated protein solution may be warmed to a temperature of at leastabout 20° C., and up to about 60° C., preferably about 25° C. to about40° C., to decrease the viscosity of the concentrated protein solutionto facilitate performance of the subsequent dilution step and micelleformation. The concentrated protein solution should not be heated beyonda temperature above which the temperature of the concentrated proteinsolution does not permit micelle formation on dilution by chilled water.The concentrated protein solution may be subject to a further defattingoperation, if required, as described in Murray II.

The concentrated protein solution resulting from the concentration stepand optional defatting step then is diluted to effect micelle formationby adding the concentrated protein solution into a body of water havingthe volume required to achieve the degree of dilution desired. Dependingon the proportion of canola protein desired to be obtained by themicelle route and the proportion from the supernatant, the degree ofdilution of the concentrated protein solution may be varied. With higherdilution levels, in general, a greater proportion of the canola proteinremains in the aqueous phase.

When it is desired to provide the greatest proportion of the protein bythe micelle route, the concentrated protein solution is diluted by about15 fold or less, preferably about 10 fold or less.

The body of water into which the concentrated protein solution is fedhas a temperature of less than about 15° C., generally about 3° C. toabout 15° C., preferably less than about 10° C., since improved yieldsof protein isolate in the form of protein micellar mass are attainedwith these colder temperatures at the dilution factors used.

The dilution of the concentrated protein solution and consequentialdecrease in ionic strength causes the formation of a cloud-like mass ofhighly associated protein molecules in the form of discrete proteindroplets in micellar form. The protein micelles are allowed to settle toform an aggregated, coalesced, dense, amorphous sticky gluten-likeprotein micellar mass. The settling may be assisted, such as bycentrifugation. Such induced settling decreases the liquid content ofthe protein micellar mass, thereby decreasing the moisture contentgenerally from about 70% by weight to about 95% by weight to a value ofgenerally about 50% by weight to about 80% by weight of the totalmicellar mass. Decreasing the moisture content of the micellar mass inthis way also decreases the occluded salt content of the micellar mass,and hence the salt content of dried isolate.

The combination of process parameters of concentrating of the proteinsolution to a protein content of at least about 200 g/L and the use of adilution factor less than about 15, result in higher yields, oftensignificantly higher yields, in terms of recovery of protein in the formof protein micellar mass from the original meal extract, and much purerisolates in terms of protein content than achieved using any of theprior art procedures (Murray IA, IB and II) referred to above.

The settled isolate, in the form of an amorphous, aggregated, sticky,gelatinous, gluten-like protein mass, termed “protein micellar mass”, orPMM, is separated from the residual aqueous phase or supernatant, suchas by decantation of the residual aqueous phase from the settled mass orby centrifugation. The PMM may be used in the wet form or may be dried,by any convenient technique, such as spray drying, freeze drying orvacuum drum drying, to a dry form. The dry PMM has a high proteincontent, in excess of about 100 wt % protein (calculated as KjeldahlNx6.25), and is substantially undenatured (as determined by differentialscanning calorimetry). The dry PMM isolated from fatty oil seed mealalso has a low residual fat content, when the procedure of Murray II isemployed, which may be below about 1 wt %.

In accordance with one aspect of the invention, particularly as it isapplied to canola protein, it has now been found that the supernatantfrom the PMM formation and settling step contains significant amounts ofcanola protein, not precipitated in the dilution step. It has notpreviously been proposed, in the Murray IA, IB and II patents, toattempt to recover additional protein from the supernatant and noobservation is made in this prior art as to any potential proteincontent of the supernatant. In accordance with this aspect of theinvention, steps are taken to recover the canola protein from thesupernatant.

In such procedure, the supernatant from the dilution step, followingremoval of the PMM, may be concentrated to increase the proteinconcentration thereof. Such concentration is effected using anyconvenient selective membrane technique, such as ultrafiltration, usingmembranes with a suitable molecular weight cut-off permitting lowmolecular weight species, including the food grade salt and othernon-proteinaceous low molecular weight materials extracted from thesource material, to pass through the membrane, while retaining canolaprotein in the solution. Ultrafiltration membranes having a molecularweight cut-off of about 3000 to 10,000 daltons having regard todiffering membranes and configurations, may be used. Concentration ofthe supernatant in this way also reduces the volume of liquid requiredto be dried to recover the protein, and hence the energy required fordrying. The supernatant generally is concentrated to a protein contentof about 100 to 400 g/L, preferably about 200 to about 300 g/L, prior todrying.

The concentrated supernatant may be dried by any convenient technique,such as spray drying, freeze drying or vacuum drum drying, to a dry formto provide a further canola protein isolate. Such further canola proteinisolate has a high protein content, usually in excess of about 90 wt %protein (calculated as Kjeldahl Nx6.25) and is substantially undenatured(as determined by differential scanning calorimetry). If desired, thewet PMM may be combined with the concentrated supernatant prior todrying the combined protein streams by any convenient technique toprovide a combined canola protein isolate. The combined canola proteinisolate has a high protein content, in excess of about 90 wt %(calculated as Kjeldahl Nx6.25) and is substantially undenatured (asdetermined by differential scanning calorimetry).

In another alternative procedure, a portion only of the concentratedsupernatant may be mixed with at least part of the PMM and the resultingmixture dried. The remainder of the concentrated supernatant may bedried as any of the remainder of the PMM. Further, dried PMM and driedsupernatant also may be dry mixed in any desired relative proportions.

By operating in this manner, a number of canola protein isolates may berecovered, in the form of dried PMM, dried supernatant and driedmixtures of various proportions by weight of PMM and supernatant,generally from about 5:95 to about 95:5 by weight, which may bedesirable for attaining differing functional and nutritional properties.

As an alternative to dilution of the concentrated protein solution intochilled water and processing of the resulting precipitate andsupernatant as described above, protein may be recovered from theconcentrated protein solution by dialyzing the concentrated proteinsolution to reduce the salt content thereof. The reduction of the saltcontent of the concentrated protein solution results in the formation ofprotein micelles in the dialysis tubing. Following dialysis, the proteinmicelles may be permitted to settle, collected and dried, as discussedabove. The supernatant from the protein micelle settling step may beprocessed, as discussed above, to recover further protein therefrom.Alternatively, the contents of the dialysis tubing may be directlydried. The latter alternative procedure is useful where small laboratoryscale quantities of protein are desired.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIG. 1, there is illustrated schematically a flow sheet ofone embodiment to the invention. Canola oil seed meal and aqueousextraction medium are fed by line 10 to an extraction vessel 12 whereinthe oil seed meal is extracted and an aqueous protein solution isformed. The slurry of aqueous protein solution and residual oil seedmeal is passed by line 14 to a vacuum filter belt 16 for separation ofthe residual oil seed meal which is removed by line 18. The aqueousprotein solution then is passed by line 20 to a clarification operation22 wherein the aqueous protein solution is centrifuged and filtered toremove fines, which are recovered by line 24.

The clarified aqueous protein solution is pumped by line 26 throughultrafiltration membrane 28 to produce a concentrated protein solutionas the retentate in line 30 with the permeate being recovered by line32. The concentrated protein solution is passed into a precipitationvessel 34 containing cold water fed by line 36. Protein micellar massformed in the precipitation vessel 34 is removed by line 38 and passedthrough a spray dryer 40 to provide dry canola protein isolate 42.

Supernatant from the precipitation vessel 34 is removed by line 44 andpumped through ultrafiltration membranes 46 to produce a concentratedprotein solution as the retentate in line 48 with the permeate beingremoved by line 50. The concentrated protein solution is passed througha spray dryer 52 to provide further dry canola protein isolate 54.

As an alternative, the concentrated protein solution in line 48 may bepassed by line 56 to mix with the protein micellar mass before themixture then is dried in spray dryer 40.

EXAMPLES Example 1

This Example illustrates the process of the invention.

‘a’ kg of commercial canola meal was added to ‘b’ L of 0.15 M NaClsolution at ambient temperature and agitated for 30 minutes to providean aqueous protein solution having a protein content of ‘c’ g/L. Theresidual canola meal was removed and washed on a vacuum filter belt. Theresulting protein solution was clarified by centrifugation to produce‘d’ L of a clarified protein solution having a protein content of ‘e’g/L.

The protein extract solution or a ‘f’ L aliquot of the protein extractsolution was reduced in volume to ‘g’ L by concentration on anultrafiltration system using ‘h’ dalton molecular weight cut-offmembranes. The resulting concentrated protein solution had a proteincontent of ‘i’ g/L.

The concentrated solution at ‘j’° C. was diluted ‘k’ into 4° C. water. Awhite cloud of protein micelles formed immediately and was allowed tosettle. The upper diluting water was removed and the precipitated,viscous, sticky mass (PMM) was recovered from the bottom of the vesselin a yield of ‘l’ wt % of the extracted protein and dried. The driedprotein was found to have a protein content of ‘m’ wt % (Nx 6.25) d.b.The product was given designation ‘n’. The parameters ‘a’ to ‘n’ areoutlined in the following Table I: TABLE I n a b c d e f g h i j k l mCPIA06-13 300 2500 13.0 1160 10.5  (1) 13 30000 303 (2) 1:10 (2) 106.5BW-AH12-G16-01 225 1500 19.6  (2) 17.5  600 30 3000 245 30 1:15 (2)104.1 BW-AL016-K15- 1200 8000 14.9  (2) 10.4  400 40 10000 257 30 1:1546 106.9 01(3) CPI-A06-33 300 2000 10.8 1800 8.7  (1) 55 30000 217 (2)1:10 (2) 104.3 A11-04 300 2000 23.2 1772 21.7 1000 52 30000 240 34 1:15(2) 107.2Notes:(1) All the protein extract solution was concentrated(2) Not determined(3) The concentrated retentate was diafiltered with 6 volumes of 0.15 MNaCl while holding the volume at 40 L prior to dilution.

Example 2

The process of Example 1 was repeated with the conditions of theprocedure being varied. A number of parameters were studied.

(a) Extraction Parameters:

The extraction parameters were varied to ascertain their effect on theconcentration of protein solution obtained. The results are tabulated inthe following TABLE II Extraction Extraction Extraction Concentration ofpH of extraction Protein concentration Temperature Time NaCl solutionsolution concentration  5% w/v 13° C. 30 min 0.15 M 6.4  5.3 g/L 15% w/v13° C. 30 min 0.15 M 6.2 12.7 g/L 15% w/v  8° C. 30 min 0.15 M —  6.6g/L 15% w/v 34° C. 30 min 0.15 M — 14.6 g/L 15% w/v 22° C. 10 min 0.15 M5.9 10.5 g/L 15% w/v 13° C. 60 min 0.15 M 5.9 10.6 g/L 10% w/v 15° C. 30min 0.15 M —  9.7 g/L 10% w/v 13° C. 70 min 0.15 M —  9.3 g/L 10% w/v13° C. 30 min 0.15 M 5.3  9.8 g/L 10% w/v 13° C. 30 min 0.15 M 6.2 10.6g/L

(b) Dilution Parameters:

The dilution parameters were varied to ascertain their effect on yieldof PMM from the dilution step. The results are tabulated in thefollowing Table III: TABLE III Protein Dilution Water Dilution PMMConcentration Temperature Ratio Recovery 206 g/L  4° C.  1:10 51.7% 258g/L  4° C.  1:10 61.8% 283 g/L  4° C.  1:10 42.6% 230 g/L 15° C.  1:10 4.5% 249 g/L  4° C. 1:5 40.4% 249 g/L  4° C. 1:3 30.7%

Example 3

This Example illustrates the effect of dilution water temperature on theyield of product protein isolate.

1200 kg of commercial canola meal was added to 8000 L of 0.15 M NaClsolution at ambient temperature and agitated 30 minutes to provide anaqueous protein solution having a protein content of 17.4 g/L. Theresidual canola meal was removed and washed on a vacuum filter belt. Theresulting protein solution was clarified by centrifugation to produce7464 L of a clarified protein solution having a protein content of 14.8g/L.

The protein extract solution was reduced in volume by concentration onan ultrafiltration system utilizing 3,000 dalton membranes. Theresulting concentrated protein solution had a protein content of 230g/L.

A 50 ml aliquot of the concentrated solution was warmed to 30° C. thendiluted 1:10 into 15° C. tap water. A slight white cloud of very smallmicelles formed and was allowed to settle. The upper diluting water wasremoved leaving a very small amount of precipitate. The precipitate onlyrepresented 4.5 wt % of the protein in the 50 ml aliquot of theconcentrated solution instead of a typical 50 wt % recovery achievedwhen diluted into 4° C. tap water. The 50 ml aliquot was taken from thebatch with the designation BW-AH012-H14-01A. The data from this Exampleare also presented in Table III above with respect to the dilutionratio.

Example 4

This Example shows the effect of temperature of concentrated solution ondilution yield.

1200 kg of commercial canola oil seed meal was added to 8000 L of 0.15 MNaCl solution at ambient temperature and agitated for 30 minutes at 13°C. to provide an aqueous protein solution having a protein content of‘a’ g/L. The residual canola meal was removed and washed on a vacuumfilter belt. The resulting protein solution was clarified bycentrifugation to produce a clarified solution having a protein contentof ‘b’ g/L.

The clarified protein solution or a ‘c’ aliquot of the protein extractsolution was reduced in volume to ‘d’ L on a ultrafiltration systemusing a ‘e’ dalton molecular weight cut-off membrane. The resultingconcentrated protein solution had a protein content of ‘f’ g/L. The lotswere given designation ‘g’.

The parameter ‘a’ to ‘g’ are given in the following Table IV: TABLE IV gBW-AL011-J16-01A BW-AL017-D11-02A a 24.4 26.3 b 20.3 18.0 c (1) 2000 d152 e 3000 5000 f 287 285.9Note:(1) All the protein extract solution was concentrated.

50 ml retentate aliquots of lot BW-AL011-J16-01A were warmed to 30° C.and 60° C. before being diluted 1:10 into 4° C. water. In each case, awhite cloud of protein micelles formed immediately and was allowed tosettle. The upper diluting water was removed and the precipitated,viscous, sticky mass (PMM) was dried. The PMM was recovered from eachexperiment and the yield of the dilution step was calculated. In thecase of the retentate temperature being 30° C., the protein recovery was57.1 wt %, while for 60° C., the yield was 23.7 wt %.

5 ml retentate aliquots of lot BW-AL017-D11-02A were warmed to varioustemperatures between 30° C. and 60° C. and then diluted at dilutionratio of 1:10 or 1:15 into 4° C. water. In each case, a white cloud ofprotein micelles formed immediately and was allowed to settle. The upperdiluting water was removed and the precipitated, viscous, sticky mass(PMM) was dried. The PMM was recovered from each experiment and theyield of the dilution step was calculated. The results obtained appearin the following Table V: TABLE V Retentate Temperature Dilution RatioPMM Yield 30° C. 1:10    49% 40° C. 1:10 49 50° C. 1:10 47 60° C. 1:1035 30° C. 1:15 51 40° C. 1:15 51 50° C. 1:15 39 60° C. 1:15 39

As may be seen from this Table, higher yields are obtained at moderatelyelevated temperatures while higher elevated temperatures tend to reduceyields.

Example 5

This Example illustrates the preparation of further canola proteinisolates using various combinations of parameters and additionallyincluding treatment with powdered activated carbon.

‘a’ kg of commercial canola meal was added to ‘b’ L of 0.15 M NaClsolution at ambient temperature and agitated ‘c’ minutes to provide anaqueous protein solution having a protein content of ‘d’ g/L. Theresidual canola meal was removed and washed on a vacuum filter belt. Theresulting protein solution was clarified by centrifugation to produce aclarified protein solution having a protein content of ‘e’ g/L.

‘f’ wt % powdered Activated Carbon (PAC) was added to the clarifiedsolution. The suspension was mixed for 15 minutes, following which thePAC was removed by filtration, resulting in ‘g’ L of a ‘h’ g/L extract.

A ‘i’ L aliquot of the protein extract solution from the PAC treatmentstep was reduced in volume to ‘j’ L on an ultrafiltration system using a30,000 dalton molecular weight cut-off membrane. The resultingconcentrated protein solution had a protein content of ‘k’ g/L.

The concentrated solution at ‘l’° C. was diluted 1: ‘m’ into 4° C. tapwater. A white cloud formed immediately and was allowed to settle. Theupper diluting water was removed and the precipitated, viscous, stickymass was dried. The dried protein which was formed had a protein contentof ‘n’ wt % protein (Nx6.25 d.b.). The overall protein recovery i.e. theaverage of dried protein isolate expressed as a percentage of theprotein solubilized in the extraction step, was ‘o’ wt %. The productwas given designation CPI ‘p’.

The specific parameters “a” to “p” for these different samples ofprotein product are set forth in the following Table VI: TABLE VI p a bc d e f g h i j k l m n o A07-15 150 1000 30 14.0 13.1 2 700 8.9 460 21246 30 10 103.5 44 A07-22 150 1000 120 13.0 12.3 4 800 8.2 800 9 490 205 106.9 (1) A08-02 300 2000 300 14.0 14.5 0.06 1300 13.8 480 6 421 25 5105.8 (1) A10-13 300 2000 45 28.6 24.9 1 2150 22.7 1000 80 176 20 10109.2 (1)Note:(1) not determined.

The effect of the addition of powdered activated carbon on colour ofcanola protein isolate is shown in Example 7 below.

Example 6

This Example illustrates an embodiment of the invention, wherein waterwas used in the extraction stage and salt was subsequently added.

150 kg of commercial canola meal was added to 1000 L of water at 13° C.,agitated for 30 minutes resulting in a protein solution with aconcentration of 4.5 g/L. The residual canola meal was removed andwashed on a vacuum filter belt. The aqueous protein solution wasclarified by centrifugation producing 1100 L of a 3.8 g/L extract.

Powdered activated carbon (PAC) was precoated on filter pads before theclarified solution was filtered producing 1000 L of a 3.2 g/L extract.

Sodium chloride was added to the latter protein solution to aconcentration of 0.15M. The volume of the protein solution was reducedto 10 L on an ultrafiltration system using 30,000 dalton membranes. Theconcentrated solution had a protein content of 292 g/L. An aliquot ofthe concentrated protein solution was warmed to 30° C. prior to dilution1:3 into 4° C. water.

A white cloud formed immediately and was allowed to settle. The upperdiluting water was removed and the precipitated, viscous, sticky mass(PMM) was dried. The dried canola protein isolate, given identificationCPI A07-18, had a protein content of 96 wt % protein (Nx6.25). Therecovery of protein was 59 wt % of the protein originally extracted.

Example 7

This Example provides a comparison of the colour of certain canolaprotein isolates produced herein in comparison to spray dried egg white,conventional soy protein isolate and products produced according toMurray II.

Samples of protein isolate were evaluated for lightness (L) andchromaticity (a and b) using a Minolta colourimeter. In the L a b colourspace, the value moves from 0 to 100, with 100 being white and 0 beingblack. The chromaticity coordinates, a and b, both have maximum valuesof +60 and −60, +a being the red direction, −a being the greendirection, +b being the yellow direction and −b being the bluedirection.

The following Table VII sets forth the results obtained: TABLE VIISample L a b Comments Egg White 90.34 −2.73 21.43 Soy Protein 85.10−0.906 14.67 The a and b values are Isolate not as close to egg white asPAC treated CPI CPI A07-15 82.77 −2.13 22.98 NaCl extraction with(Example 5) CPI A07-18 82.80 −2.69 25.19 Water extraction with PAC(Example 6) CPI A06-33 75.60 0.404 26.51 NaCl extraction without PAC(Example 1) CPI A08-02 80.04 −2.87 23.37 NaCl extraction with low(Example 5) (0.06%) PAC Murray II 65.81 0.962 18.27 Relatively darkproduct

The results set forth in Table VII show the beneficial effect on colour,namely more white, less yellow, by the use of powdered activated carbon.

Example 8

This Example illustrates the preparation of further canola proteinisolate including protein recovered from supernatant.

‘a’ kg of commercial canola meal was added to ‘b’ L of 0.15 M NaClsolution at ambient temperature and agitated for 30 minutes to providean aqueous protein solution having a protein content of ‘c’ g/L. Theresidual canola meal was removed and washed on a vacuum filter belt. Theresulting protein solution was clarified by centrifugation to produce aclarified protein solution having a protein content of ‘d’ g/L followedby the addition of 1 wt % Powdered Activated Carbon (PAC).

The suspension was mixed for 15 minutes, following which the PAC wasremoved by filtration, resulting in ‘e’ L of a ‘f’ g/L extract.

A ‘g’ L aliquot of the protein extract solution from the PAC treatmentstep was reduced in volume to ‘h’ L on an ultrafiltration system using30,000 dalton molecular weight cut-off membranes. The resultingconcentrated protein solution had a protein content of ‘i’ g/L.

The concentrated solution at ‘j’° C. was diluted 1: ‘k’ into 4° C.water. A white cloud formed immediately and was allowed to settle. Theupper diluting water was removed and was reduced in volume byultrafiltration using 3000 dalton molecular weight cut-off membranes bya volume reduction factor of ‘l’. The concentrate was added to theprecipitated, viscous, sticky mass and the mixture was dried. The driedprotein mixture which was formed had a protein content of ‘m’ wt % ofprotein (Nx6.25). The product was given designation CPI ‘n’.

The specific parameters ‘a’ to ‘n’ for two different samples of proteinproduct are set forth in the following Table VIII: TABLE VIII n a b c de f g h i j k l m A10-04 300 2000 28.4 27.6 1330 16.3 200 18 186 28 1011 100.3 A10-05 300 2000 27.7 21.9 1320 21.9 300 20 267 27 15 21 102.3

Example 9

This Example further illustrates the preparation of further canolaprotein isolate including protein recovered from supernatant without PACtreatment.

‘a’ kg of canola meal was added to ‘b’ L of 0.15 M NaCl solution at atemperature of 20° C. and agitated for 30 minutes to provide an aqueousprotein solution having a protein content of ‘c’ g/L. The resultingcanola meal was removed and washed on a vacuum filter belt. Theresulting protein solution was clarified by centrifugation andfiltration to produce a clarified protein solution having a proteincontent of ‘d’ g/L.

The protein extract solution or a ‘e’ L aliquot of the protein extractsolution was reduced in volume on an ultrafiltration system usingmembranes having a molecular weight cut-off of ‘f’ daltons. Theresulting concentrated protein solution had a protein content of ‘g’g/L.

The concentrated solution at ‘h’° C. was diluted ‘i’ into ‘j’° C. water.A white cloud immediately formed and was allowed to settle. The upperdiluting water was removed and concentrated by ultrafiltration using3000 dalton molecular weight cut-off membranes to provide a concentratedsupernatant having a protein content of ‘k’ g/L. The concentrate wasadded to the precipitated, viscous, sticky mass and the mixture dried.

The dried protein mixture was found to have a protein content of ‘1’ wt% (Nx6.25). The yield of canola protein isolate from the proteinsolution extract was ‘m’ wt %. The product was given designation ‘n’.

The specific parameters “a” to ‘n’ for two different samples of proteinproduct are set forth in the following Table IX: TABLE IX nBW-AL11-I21-01A A11-01 a 1200 300 b 8000 2000 c 24.5 23.7 d 17.8 20.7 e(1) 400 f 3000 30,000 g 284.7 200.2 h 31 32 i 1:10 1:15 j 8 4 k 279.0104.7 l 100.2 102.8 m 68.1 (2)Note:(1) All the protein extract solution was concentrated(2) not determined

Example 10

This Example illustrates extraction of the canola protein meal at arelatively high pH and recovery of protein from supernatant.

150 kg of commercial canola meal was added to 2000 L of 0.15 M NaClhaving a pH adjusted to 9.5 by the addition of sodium hydroxide atambient temperature, agitated for 30 minutes to provide an aqueousprotein solution having a protein content of 13.2 g/L. The residualcanola meal was clarified by centrifugation and filtration to produce1210 L of a clarified protein solution having a protein content of 12.1g/L.

The pH of the clarified protein solution was adjusted to 6.2 by theaddition of hydrochloric acid. A 900 L aliquot of the protein extractsolution was reduced in volume to 50 L by concentration on anultrafiltration system using 3000 dalton molecular weight cut-offmembranes. The resulting concentrated protein solution had a proteincontent of 276.2 g/L.

The concentrated solution at 30° C. was diluted 1:15 into 4° C. water. Awhite cloud formed immediately and was allowed to settle. The upperdiluting water was removed and 390 L of this supernatant wereconcentrated by 24 L by ultrafiltration using 3000 dalton molecularweight cut-off membranes to provide a concentrated supernatant having aprotein content of 149.0 g/L. The concentrate was added to theprecipitated, viscous, sticky mass and the mixture dried.

The dried protein mixture was found to have a protein content of 103.3wt % (Nx 6.25). The yield of canola protein isolate from the proteinsolution extract was 48.3 wt %. The product was given designationBW-AL017-D08-02A.

Example 11

This Example illustrates the preparation of canola protein isolate byprocessing of supernatant.

‘a’ kg of commercial canola meal was added to ‘b’ L of 0.15 M NaClsolution at ambient temperature and agitated for 30 minutes to providean aqueous protein solution having a protein content of ‘c’ g/L. Theresidual canola meal was removed and washed on a vacuum filter belt. Theresulting protein solution was clarified by centrifugation to produce aclarified protein solution having a protein content of ‘d’ g/L.

The clarified protein solution was reduced in volume on anultrafiltration system using 3,000 dalton molecular weight cut-offmembranes. The resulting concentrated solution had a protein content of‘e’ g/L.

The concentrated solution at ‘f’° C. was diluted ‘g’ into 4° C. water. Awhite cloud formed immediately and was allowed to settle. The upperdiluting water was removed and the precipitated, viscous, sticky mass(PMM) was recovered from the bottom of the vessel and dried. The driedprotein was found to have protein content of ‘k’ wt % (Nx6.25) d.b.

The removed upper diluting water was reduced in volume byultrafiltration using 3,000 dalton molecular weight cut-off membranes toa protein concentration of ‘i’ g/L. The concentrate then was dried. Thedried protein which was formed had a protein content of ‘j’ wt %(Nx6.25). The product was given designation ‘l’.

The specific parameters ‘a’ to ‘l’ for two different samples of proteinproduct are set forth in the following Table X: TABLE X l AL016-J24AL011-J16-01A a 1200 1200 b 8000 8000 c 22.7 24.4 d 16.9 20.3 e 281 287f 37 28 g 1:10 1:10 h (2) 101.9 i (3) 265 j 103.9 101.5 k (2) 101.6Note:(1) All the protein extract solution was concentrated(2) Not determined(3) The supernatant was concentrated by a volume reduction factor of 16.

Example 12

This Example illustrates application of the process of the invention tocold pressed canola meal and the recovery of additional protein from thesupernatant.

50 kg of canola meal was pressed and 13 L of oil recovered. 30 kg of theresulting crushed meal was added to 300 L of 0.15M NaCl solution at 20°C. and the mixture was agitated for 40 minutes, followed by a thirtyminute settling period. 200 L of aqueous protein solution were obtainedhaving a protein content of 19.5 mg/ml.

The aqueous protein solution was chilled to 4° C. and refrigerated atthat temperature for 16 hours, to permit fat present in the meal andextracted in the extraction step, to separate, according to theprocedure of Murray II. The resulting fat layer was removed from thesurface of the aqueous protein solution. The remaining aqueous proteinsolution was filtered through a filter press having a 20 μm filter padto remove remaining particles of hull and cell wall material as well asresidual particles of fat. 200 L of filtrate with a protein content of14.6 mg/ml were obtained.

The aqueous protein solution was reduced in volume to 10.5 L byconcentration on an ultrafiltration system using 10,000 dalton molecularweight cut-off membranes. The resulting concentrated protein solutionhad a protein content of 200 g/L, which represented a yield of 67 wt %of the protein originally extracted from the canola meal. The resulting10.5 L solution was again chilled to 4° C. and refrigerated at thistemperature for 16 hours. The solution was then centrifuged at 10,000×gfor five minutes and the separated fat removed from the concentratedprotein solution.

The protein solution was warmed to 30° C. and was added to water at 4°C. at a dilution ratio of 1:9. Following overnight settling, 85 L ofsupernatant was decanted leaving approximately 9 L of precipitated,viscous, sticky mass (PMM). The PMM was further concentrated bycentrifugation at 10,000×g for 5 minutes and an aliquot of thecentrifuged PMM was freeze dried to determine its protein content. Thefreeze dried PMM was found to have a protein content of 105.5 wt %(Nx6.25).

The supernatant from the PMM formation step was concentrated to 11L byconcentration on a ultrafiltration system using 10,000 dalton molecularweight cut-off membranes. This latter concentrated solution had aprotein concentration of 89.7 mg/ml. An aliquot of this concentratedsolution was freeze dried to determine the protein content. Thefreeze-dried protein was found to have a protein content of 101.7 wt %(Nx6.25).

The overall yield of protein as PMM and recovered from the supernatantfrom the protein extracted from the canola meal was 50 wt %.

Example 13

This Example illustrates application of the process of the invention tohigh erucic acid rapeseed.

35 kg of commercial high erucic acid rapeseed meal was added to 350 L of0.3 M NaCl solution (10% w/v) at 15° C. and agitated for one hour toprovide an aqueous protein solution having a protein content of 7.71g/L. A second run under the same conditions produced an aqueous proteinsolution having a protein content of 7.36 g/L. The extract solutionswere decanted and clarified by filtration through 20 μm filter pads toremove residual meal and to provide a total filtrate volume of 550 L.

The filtrate then was concentrated to 9 L using a hollow fibreultrafiltration system having 10,000 dalton molecular cut-off membranes.The resultant concentrated protein solution had a protein content of 232g/L.

The concentrated protein solution, at a temperature of 30° C., was thendiluted 1:9 into 4° C. water. A white cloud immediately formed and wasallowed to settle for 16 hours at 4° C. 80 L of supernatant was decantedand was reduced in volume by diafiltration concentration to a volume of7 L of concentrated supernatant having a protein content of 47.7 g/L.

The settled viscous sticky mass (PMM) was collected and freeze dried. Aone litre portion of the concentrated supernatant was freeze dried. 1393g of freeze dried PMM was obtained from the process having a proteincontent of 106 wt % (Nx6.25). 1 L of freeze-dried concentratedsupernatant yielded 67 g, so that the 7 L of concentrated supernatantcontained 469 g of dried protein, for an overall protein yield from theprotein extracted from the oil seed meal of 47 wt %. The freeze-driedconcentrated supernatant had a protein content of 83 wt % (Nx6.25) sothat a mixture of PMM and protein from concentrated supernatant has aprotein content of 102 wt % (Nx6.25) on a dry weight basis.

Example 14

This Example illustrates application of the invention to mustard seed.

75 g of commercial mustard seed meal was added to 750 ml of 0.15 M NaClsolution (15% w/w) at 20° C. and agitated for 30 minutes. The extractionslurry was centrifuged at 10,000×g for 10 minutes to separate the spentmeal from the extracted protein. The resulting 500 ml of proteinsolution having a protein content of 18.05 mg/ml was then filteredthrough Whatman #4 filters in order to further clarify the solution.

The clarified solution was concentrated to 27 ml on a Milliporemini-ultrafiltration stirred cell system using 10,000 molecular weightcut-off membranes. The resulting concentrated protein solution had aprotein concentration of 218 g/L.

22.2 ml of the total 27 ml of concentrated protein solution, at atemperature of 30° C., was then diluted 1:9 into 4° C. tap water. Awhite cloud immediately formed and was allowed to settle for 16 hours at4° C. 200 ml of supernatant was decanted.

The settled viscous, sticky mass (PMM) was collected and centrifuged at10,000×g for 5 minutes to reduce the moisture content of the pellet,which then was freeze dried. 4.48 g of freeze-dried pellet was obtained,representing a yield of protein in the freeze-dried pellet from theprotein in the protein extracted from the oil seed meal was 50 wt % (ifthe entire 27 ml of retentate had been diluted, the final yield isextrapolated to be approximately 60 wt %). The freeze-dried PMM obtainedfrom the process had a protein content of 103 wt % (Nx 6.25).

Example 15

This Example illustrates application of the process of the invention tonon-GMO canola.

450 g of non-GMO canola meal was added to 3 L of 0.15 M NaCl solution(15% w/w) at 20° C. and agitated for 30 minutes to provide an aqueousprotein solution having a protein content of 8.08 g/L. The mixture wasallowed to stand for 30 minutes to permit residual meal and proteinsolution to separate. The protein solution was decanted, centrifuged for10 minutes at 10,000×g and filtered through Whatman #4 filter paper tofurther clarify the solution.

The filtrate then was concentrated to a volume of 17 ml using a hollowfibre ultrafiltration system having 10,000 dalton molecular cut-offmembranes. The resultant concentrated protein solution has a proteincontent of 205 g/L.

A 14 ml sample of the retentate, at a temperature of 30° C., was thendiluted 1:9 into 4° C. tap water. A white cloud immediately formed andwas allowed to settle. The supernatant was decanted and the settledviscous sticky mass (PMM) was collected and freeze-dried. 2.3 g offreeze-dried PMM was obtained from the process having a protein contentof 103 wt % (Nx 6.25).

The overall yield of protein with respect to the protein extract fromthe oil seed meal was 41 wt %. If the entire 17 ml of retentate had beendiluted approximately 2.66 g of dried protein would have been recoveredfor a yield of 46 wt %.

Example 16

This Example illustrates recovery of canola protein isolate by adialysis procedure.

‘a’ kg of commercial canola meal was added to ‘b’ L of 0.15 M NaClsolution at ambient temperature and agitated for 30 minutes to providean aqueous protein solution having a protein content of ‘c’ g/L. Theresidual canola meal was removed and washed on a vacuum filter belt. Theresulting protein solution was clarified by centrifugation to produce‘d’ L of a clarified protein solution having a protein content of ‘e’g/L.

A ‘f’ aliquot of the protein extract solution was reduced in volume to‘g’ L by concentration on an ultrafiltration system using ‘h’ daltonmolecular weight cut-off membranes. The resulting concentrated solutionhad a protein content of ‘i’ g/L. The retentate was given designation‘j’. The parameters ‘a’ to ‘j’ are outlined in the following Table XI:TABLE XI j BW-AL017-D17-02A BW-AL017-D22-02A a 150 150 b 1004 1003 c25.1 27.1 d 1080 1132 e 18.0 16.5 f 710 1092 g 22.5 31.5 h 5000 5000 i291.6 362.5

3.5 L of retentate from BW-AL017-D17-02A was dialyzed in 120 L of 4° C.water. The water was changed daily for several days and running waterwas used for the last two days. The conductivity of the retentatedropped from 6.89 millisiemens (ms) to 0.32 ms. As the conductivitydropped, micelles began to form in the retentate. At the completion ofthe dialysis, a large amount of PMM was present at the bottom of eachdialysis tube. The PMM was recovered and dried. The canola proteinisolate had a protein content of 103.0 wt % d.b.

The procedure was repeated with the retentate BW-AL017-D22-02A exceptthat the dialysis was carried out in 60° C. water. As the conductivitydecreased, the solution became cloudy but very little micelle formationoccurred. Once the dialyzed solution was cooled to 110C, micelleformation occurred. The resulting PMM, when dried, had a protein contentof 106 wt % of d.b.

Sumary of Disclosure

In summary of this disclosure, the present invention provides a novelprocedure for isolating protein from oil seeds in improved yields andprotein content than has previously been achieved. Modifications arepossible within the scope of this invention.

1.-34. (canceled)
 35. A canola protein isolate having a protein contentof at least about 90 wt % as determined by Kjeldahl nitrogen x6.25 on adry weight basis produced by a method which comprises: (a) extracting acanola oil seed meal at a temperature of at least about 5° C. to causesolubilization of protein in said oil seed meal and to form an aqueousprotein solution having a protein content of about 5 to about 30 g/L anda pH of about 5 to about 6.8, (b) separating the aqueous proteinsolution from residual canola oil seed meal, (c) increasing the proteinconcentration of said aqueous protein solution to at least about 200 g/Lwhile maintaining the ionic strength substantially constant by using aselective membrane technique to provide a concentrated protein solution,(d) diluting said concentrated protein solution into chilled waterhaving a temperature below about 15° C. to cause the formation ofprotein micelles, (e) settling the protein micelles to form anamorphous, sticky, gelatinous, gluten-like micellar mass, and (f)following recovering the protein micellar mass therefrom, concentratingthe supernatant to a protein concentration of about 100 to about 400q/L, and (g) drying the concentrated supernatant to provide the canolaprotein isolate.
 36. A canola protein isolate having a protein contentof at least about 90 wt % as determined by Kjeldahl nitrogen x6.25 on adry weight basis produced by a method which comprises: (a) extracting acanola oil seed meal at a temperature of at least about 5° C. to causesolubilization of protein in said oil seed meal and to form an aqueousprotein solution having a protein content of about 5 to about 30 g/L anda pH of about 5 to about 6.8, (b) separating the aqueous proteinsolution from residual canola oil seed meal, (c) increasing the proteinconcentration of said aqueous protein solution to at least about 200 g/Lwhile maintaining the ionic strength substantially constant by using aselective membrane technique to provide a concentrated protein solution,(d) diluting said concentrated protein solution into chilled waterhaving a temperature below about 15° C. to cause the formation ofprotein micelles, (e) settling the protein micelles to form anamorphous, sticky, gelatinous, gluten-like micellar mass, (f) recoveringthe protein micellar mass from supernatant having a protein content ofat least about 100 wt % as determined by Kieldahl nitrogen x6.25 on adry weight basis, (g) following recovering of the protein micellar masstherefrom, concentrating the supernatant to a protein concentration ofabout 100 to about 400 g/L, (h) mixing the concentrated supernatant withthe recovered protein micellar mass, and (g) drying the mixture toprovide the canola protein isolate.
 37. A canola protein isolate havinga protein content of at least about 90 wt % as determined by Kjeldahlnitrogen x6.25 on a dry weight basis produced by a method whichcomprises: (a) extracting a canola oil seed meal at a temperature of atleast about 5° C. to cause solubilization of protein in said oil seedmeal and to form an aqueous protein solution having a protein content ofabout 5 to about 30 g/L and a pH of about 5 to about 6.8, (b) separatingthe aqueous protein solution from residual canola oil seed meal, (c)increasing the protein concentration of said aqueous protein solution toat least about 200 g/L while maintaining the ionic strengthsubstantially constant by using a selective membrane technique toprovide a concentrated protein solution, (d) diluting said concentratedprotein solution into chilled water having a temperature below about 15°C. to cause the formation of protein micelles, (e) settling the proteinmicelles to form an amorphous, sticky, gelatinous, gluten-like micellarmass, (f) recovering the protein micellar mass from supernatant having aprotein content of at least about 100 wt % as determined by Kieldahlnitrogen x6.25 on a dry weight basis, (f) following recovery of theprotein micellar mass therefrom, concentrating the supernatant to aprotein concentration of about 100 to about 400 g/L, (g) mixing aportion of said concentrated supernatant with at least a portion of therecovered protein micellar mass, and (h) drying the resulting mixture toprovide the canola protein isolate.
 38. A canola protein isolate havinga protein content of at least about 90 wt % as determined by Kjeldahlnitrogen x6.25 on a dry weight basis produced by a method whichcomprises: (a) extracting a canola oil seed meal at a temperature of atleast about 5° C. to cause solubilization of protein in said oil seedmeal and to form an aqueous protein solution having a protein content ofabout 5 to about 30 q/L and a pH of about 5 to about 6.8, (b) separatingthe aqueous protein solution from residual canola oil seed meal, (c)increasing the protein concentration of said aqueous protein solution toat least about 200 g/L while maintaining the ionic strengthsubstantially constant by using a selective membrane technique toprovide a concentrated protein solution, (d) diluting said concentratedprotein solution into chilled water having a temperature below about 15°C. to cause the formation of protein micelles, (e) settling the proteinmicelles to form an amorphous, sticky, gelatinous, gluten-like micellarmass, (f) recovering the protein micellar mass from supernatant having aprotein content of at least about 100 wt % as determined by Kieldahlnitrogen x6.25 on a dry weight basis, (f) following recovery of theprotein micellar mass therefrom, concentrating the supernatant to aprotein concentration of about 100 to about 400 g/L, (g) mixing aportion of said concentrated supernatant with at least a portion of therecovered protein micellar mass, and (h) drying the resulting mixture toprovide the canola protein isolate (i) drying the remainder of theconcentrated supernatant and any remainder of the recovered proteinmicellar mass is dried. 39.-42. (canceled)
 43. A canola protein isolatehaving a protein content of at least about 90 wt % as determined byKjeldahl nitrogen x6.25 on a dry weight basis produced by the processwhich comprises: (a) extracting a canola oil seed meal at a temperatureof at least about 5° C. to cause solubilization of protein in said oilseed meal and to form an aqueous protein solution having a proteincontent of about 5 to about 30 g/L and a pH of about 5 to about 6.8, (b)separating the aqueous protein solution from residual canola oil seedmeal, (c) increasing the protein concentration of said aqueous proteinsolution to at least about 200 g/L while maintaining the ionic strengthsubstantially constant by using a selective membrane technique toprovide a concentrated protein solution, (d) diluting said concentratedprotein solution into chilled water having a temperature below about 15°C. to cause the formation of protein micelles, (e) settling the proteinmicelles to form an amorphous, sticky, gelatinous, gluten-like micellarmass, and (f) following recovering of the protein micellar masstherefrom, processing the supernatant to recover additional qualities ofcanola protein isolate therefrom.
 44. The canola protein isolate ofclaim 35 wherein said supernatant is concentrated to a proteinconcentration of about 200 to about 300 g/L.
 45. The canola proteinisolate of claim 36 wherein said supernatant is concentrated to aprotein concentration of about 200 to about 300 g/L.
 46. The canolaprotein isolate of claim 37 wherein said supernatant is concentrated toa protein concentration of about 200 to about 300 g/L.